Plasma etching apparatus and plasma etching method

ABSTRACT

A plasma processing apparatus having a plasma generating unit, a process chamber capable of having an inside pressure thereof reduced, a process gas supply unit for supplying gas in the process chamber, a specimen table for holding a specimen, a vacuum pumping unit, and a monitor unit. The process chamber includes an outer cylinder having the capability of withstanding a reduced pressure, and an inner cylinder arranged inside the outer cylinder. The monitor unit enables monitoring of a temperature of the inner cylinder of the process chamber continuously or optionally at a time of processing a specimen.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation application of Ser. No.09/983,946, filed Oct. 26, 2001, which is a continuation application ofSer. No. 09/421,044, filed Oct. 20, 1999, which is a divisionalapplication of Ser. No. 09/227,332, filed Jan. 8, 1999, now U.S. Pat.No. 6,171,438, which is a continuation-in-part application of Ser. No.08/611,758, filed Mar. 8, 1996, now U.S. Pat. No. 5,874,012, entitled“Plasma Processing Apparatus and Plasma Processing Method”, by some ofthe inventors herein, the subject matter of the aforementionedapplications being incorporated by reference herein.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a plasma etching apparatus andetching method and, more particularly, to a plasma etching apparatus andetching method suitable for forming a fine pattern in the semiconductormanufacture process.

[0003] In the semiconductor manufacture process, the plasma etchingapparatus is widely used in the fine processing processes, for example,such as film deposition, etching, and ashing. The process by plasmaetching performs the predetermined process by making processing gasintroduced into the vacuum chamber (reactor) plasmatic by the plasmageneration means, performing the fine processing by making it react onthe surface of a semiconductor wafer, and discharging volatile reactionproducts.

[0004] In this plasma etching process, the temperatures of the innerwall of the reactor and wafer and the deposition status of reactionproducts on the inner wall greatly affect the process. If reactionproducts deposited inside the reactor are peeled off, dust may becaused, resulting in deterioration of the element characteristics andreduction of the yield.

[0005] Therefore, in the plasma etching apparatus, to keep the processstable and control generation of foreign substances, it is important tocontrol the temperature in the reactor and deposition of reactionproducts on the surface.

[0006] For example, in Japanese Patent Application Laid-Open 8-144072,for the purpose of improving the selection ratio in the dry etchingprocess of a silicon oxide film, a dry etching apparatus for controllingand holding the temperature of each unit inside the reactor at a hightemperature within a range of 150° C. to 300° C. (desirably from 200° C.to 250° C.) which is higher than the temperature at the etching stage of150° C. or more with the accuracy of less than ±5° C. is described. Whenthe temperature of each unit of the inner surface of the reactor isincreased and controlled at a high value by heating like this, thedeposited amount of plasma polymeric products on the inner surface ofthe reactor reduces, and the deposited amount of plasma polymericproducts on a semiconductor wafer increases, and the selection improves.

[0007] In Japanese Patent Application Laid-Open 5-275385, a parallelplate type plasma etching apparatus in which a heating means forincreasing and keeping the temperature so that reaction productsgenerated by the plasma etching will not be deposited is installed on atleast one of the clamp ring (workpiece holding means) and focus ring(plasma centralization means) is described. As a heating means, aresistance heating element is used. Deposition of reaction products canbe prevented by heating, so that peeling of reaction products anddeposition of particles on the surface of a workpiece can be reduced.

[0008] As mentioned above, in the plasma etching apparatus, it isimportant to control the temperature of the surface of the inner wall ofthe chamber and deposition of reaction products on the surface of theinner wall.

[0009] However, when the temperature of the inner wall surface of thechamber, particularly the temperature of the side wall surface having awide area is set to a high value between 200° C. and 250° C. or more,the etching characteristic becomes very sensitive to the temperature ofthe inner wall surface and a problem arises that the reproducibility andreliability of the process are apt to reduce.

[0010] For example, in S. C. McNevin, et al., J. vac. Sci. Technol. B15(2) March/April 1997, p. 21, Chemical challenge of submicron oxideetching’, it is indicated that when the side wall temperature changesfrom 200° C. to 170° C. in inductive coupling plasma, the oxide filmetching rate increases more than 5%. As a reason, it is inferred thatsince the side wall temperature lowers, much more carbon is adsorbedinto the wall, and deposition of carbon on a wafer reduces, and theoxide film etching rate increases. As mentioned above, since highdensity plasma, particularly, performs a strong interaction with theinner wall of the reactor in the high temperature zone, deposition ofreaction products on the inner wall surface and composition change ofthe surface proceed rapidly due to a change in the temperature balanceinside the reactor and appear as a change in the etching characteristic.

[0011] Furthermore, in the high temperature zone, the aforementionedinteraction between the plasma and the inner wall becomes very sensitiveto a change in temperature. For example, when SiO₂ is used as a materialof the inner wall surface, a thermodynamic relationship between theetching rate by F atoms of SiO₂ and the wall temperature is reported (D.L. Flamm, et al., J. Appl. Phys., 50, p. 6211 (1979)), and when thisrelationship is applied to a temperature zone of more than 150° C., theetching rate rapidly increases exponentially when the wall temperatureis between 200° C. and 250° C. or more.

[0012] Therefore, in such a high temperature zone, the temperaturecontrol requires high accuracy such as ±5° C. max. However, the innerwall surface is exposed to high density plasma, so that it is not easyto control the wall surface temperature with high accuracy in such ahigh temperature zone. To realize it, a temperature detection means anda heating means such as a heater and lamp are used for temperaturecontrol, though the temperature control mechanism and means are largelyscaled. Furthermore, in such a high temperature zone, reaction productsare not deposited on the inner wall surface, so that the wall surface isetched and consumed by plasma. Therefore, it is necessary toperiodically exchange the parts of the inner wall surface and anincrease in the cost of expendable supplies results. Heating requireslarge energy, thus the high temperature zone is not desirable also froma viewpoint of energy consumption.

[0013] The same problem is imposed also by heating the ring around awafer and the electrode. When the ring is heated to increase thetemperature thereof, deposition of reaction products can be prevented,though the heating mechanism such as the resistance heating elementmakes the equipment constitution complex. When the ring and inner wallsurface are etched and consumed by plasma even if deposition of reactionproducts can be prevented, there is the possibility that theconstitution material itself will become a new dust source. Furthermore,when the parts of the ring and inner wall surface are consumed, it isnecessary to periodically exchange them and the running cost of theequipment increases.

[0014] One method for solving such a problem is to protect the innerwall surface of the chamber by a surface coating layer of a polymer. Forexample, in Japanese Patent Application Laid-Open 7-312363, a plasmaetching apparatus for keeping the temperature of the workpiece (articleto be processed) holder higher than that of the wall surface of thechamber and forming a surface coating layer on the inner wall surface ofthe chamber is described. By catching and storing contaminant particlesin a polymer film, remaining and storing of contaminants in the chamberdue to reaction products can be reduced.

[0015] However, the purpose in this case is not to protect the wallsurface but to catch contaminant particles. It is just described thatthe temperature for forming a surface coating layer on the inner wallsurface of the chamber is lower than that of a workpiece (article to beprocessed) by more than 5° C. and the temperature range and controlaccuracy are not taken into account. The pressure range is a highpressure range such as several hundreds mtorr (several tens Pa).However, it is inferred that the deposition temperature of a filmchanges the composition and quality of the film and affects the filmpeeling strength and occurrence of foreign substances. It is expectedthat changing of the deposited film temperature results in occurrence ofcracking and peeling due to repetition of thermal expansion and shrinkand causes foreign substances and the temperature control accuracy is animportant factor. Within a pressure range of several tens mtorr max.(several Pa max.), it is considered that the film deposition conditionvaries due to high ion energy and a longer mean free distance ofmolecules, Furthermore, in the aforementioned prior art, it is necessaryto remove the coating layer catching contaminants from the wall surfaceof the plasma etching chamber and it directly affects the throughput ofthe equipment and the cost of expendable supplies. However, this respectis not taken into account.

SUMMARY OF THE INVENTION

[0016] The present invention is designed to eliminate the difficultiesmentioned above and an object of the present invention is to provide aplasma etching apparatus maintaining the reproducibility and reliabilityof the process at a low cost for a long period of time so as to preventthe etching characteristic from a change with time by controlling theinner temperature of the reactor and deposition of reaction products.

[0017] The inventors have given diligent study to the aforementionedproblems and as a result of it, found that when the inner wall surfacetemperature in the reactor is controlled to a temperature sufficientlylower than that of a wafer and a constant temperature within a pressurerange of several Pa max. in the reactor, a strong coating film is formedon the inner wall surface. As a result of more detailed analysis, theinventors have acknowledged that this coating film is polymerized muchmore when the temperature at film forming time is lower, and when thetemperature at film forming time is controlled constant, a solid layerstructure is formed, accordingly the film surface is not peeled off anddamaged and dust is not caused.

[0018] In the above description, that the inner wall surface temperaturein the reactor is “sufficiently lower than that of a wafer and constant”means that the temperature is controlled with the accuracy of less than±10° C. within a range lower than that of a wafer by 5° C. or more,desirably within a range lower by 20° C. or more. When the temperatureof a wafer during processing is almost within a range from 100° C. to110° C., it means that the temperature range is 100° C. or lower,desirably 80° C. or lower.

[0019] On the other hand, in the reactor, there is a part or a componentpart where the control in the aforementioned low temperature zone isdifficult. The inventors have given study also to such a part and as aresult of it, found a method for controlling the temperature anddeposition of reaction products on the surface without using acomplicated heating mechanism such as a heating resistor.

[0020] The present invention is designed on the basis of theaforementioned acknowledge and provides a plasma etching apparatuscomprising a vacuum processing chamber, a plasma generation device, aprocessing gas supply means for supplying gas to the processing chamber,an electrode for holding a sample to be processed in this vacuumprocessing chamber, and an evacuation system for reducing the pressureof the vacuum processing chamber, which is characterized in that theprocessing gas includes at least one kind of gas having a compositionfor forming a polymerized film by plasma discharge, and the processinggas is made plasmatic by plasma discharge in the processing chamber, andat least one part of the inner wall surface (or the surface of aninternal component part) in contact with plasma in the processingchamber is controlled to a constant temperature which is sufficientlylower than that of a sample, and a strong polymerized film is formed onthe inner wall surface of the processing chamber.

[0021] Another characteristic of the present invention is that thetemperature of the inner wall surface for forming the aforementionedpolymerized film is controlled with the accuracy of less than ±10° C.within a range lower than that of the sample by 5° C. or more, desirablywithin a range lower by 20° C. or more.

[0022] Another characteristic of the present invention is that theprocessing pressure in the processing chamber is set within a range from0.1 Pa to 10 Pa, desirably from 0.5 Pa to 4 Pa.

[0023] Another characteristic of the present invention is that themember constituting the inner wall surface of the processing chamber forforming the aforementioned polymerized film has a structure that it canbe easily exchanged.

[0024] Another characteristic of the present invention is that theapparatus includes a process of controlling the growth of theaforementioned polymerized film formed on the inner wall surface of theprocessing chamber.

[0025] Still another characteristic of the present invention is that inthe plasma etching apparatus comprising a vacuum processing chamber, aplasma generation device, a processing gas supply means for supplyinggas to the processing chamber, an electrode for holding a sample to beprocessed in this vacuum processing chamber, and an evacuation systemfor reducing the pressure of the vacuum processing chamber, thecomponent part (or the inner wall surface) in contact with plasma in theprocessing chamber is structured so that the bias power is applied to atleast one part of the component part, and the heat capacity thereof ismade sufficiently small, and the surface area thereof is made smaller.

[0026] Another characteristic of the present invention is that thetemperature of the component part in contact with plasma in theprocessing chamber is adjusted within a range from 100° C. to 250° C.,desirably from 150° C. to 200° C. and furthermore, the processingpressure is set within a range from 0.1 Pa to 10 Pa, desirably from 0.5Pa to 4 Pa.

[0027] Another characteristic of the present invention is that thecomponent part of the inner wall is ring-shaped and the surface area ofthe part in contact with plasma is 20% of the total area of the innerwall of the processing chamber or less.

[0028] Another characteristic of the present invention is that thecomponent part in contact with plasma in the processing chamber, inwhich the bias power is applied to at least one part thereof isring-shaped, and the thickness thereof is 6 mm or less, and the innerdiameter thereof is more than the diameter of a sample

[0029] Still another characteristic of the present invention is that theplasma etching apparatus is structured so that an infrared absorber isformed in the neighborhood of the side of the component part of theinner wall which is in contact with plasma and the temperature of thepart is remotely controlled by the infrared radiation means.

[0030] Another characteristic of the present invention is that thetemperature of the part whose temperature is controlled by theaforementioned infrared radiation is controlled with the accuracy ofless than ±10° C. within a range from 100° C. to 250° C., desirably from150° C. to 200° C.,

[0031] Still another characteristic of the present invention is that inthe plasma etching apparatus, the plasma generation apparatus is amagnetic field UHF band electromagnetic wave radiation and dischargesystem.

[0032] According to the present invention, a part of processing gas ispolymerized by plasma discharge and a surface coating layer is formed bypolymer on the part of the inner wall of the processing chamber which isin contact with plasma or the surface of the part. By controlling thetemperature of the inner wall surface of the reactor to a constanttemperature sufficiently lower than that of a wafer, the polymerizationof the coating layer proceeds and a solid layer structure can be formed.Therefore, the inner wall surface will not be etched and consumed byplasma, so that the frequency of part exchange of the inner wall surfacecan be reduced and the running cost can be decreased. Even if thecoating layer is exposed to plasma, peeling and damage are not caused tothe surface thereof because the film composition is dense, so that dustwill not be caused.

[0033] Since the temperature of the inner wall surface is set in atemperature zone lower than that of a wafer, as compared with a casethat the temperature of the inner wall surface is set in a hightemperature zone of 200° C. or more, the interaction between plasma andthe inner wall surface is weak and not sensitive to a change intemperature. As a result, the reproducibility and reliability of theprocess hardly reduce for a long period of time and the accuracy oftemperature control may be, for example, less than ±10° C. and can berealized comparatively easily without using a complicated mechanism fortemperature control.

[0034] When a polymerized film exceeding a predetermined value is formedon the inner wall surface, it is necessary to remove this film. When theequipment is exposed to the air, and the component part of the innerwall surface of the processing chamber on which the polymerized film isformed is exchanged, and the equipment is reoperated, and the film isremoved by wet cleaning on an ex-situ basis after removal from thechamber instead of plasma cleaning, and the inner wall surface isreproduced, satisfactory results can be produced such that thenon-operation time of the equipment is reduced, and the throughput isprevented from reduction, and the cost of expendable supplies can bereduced by reproduction and repetitive use of parts. When a process ofcontrolling the growth of the polymerized film is added to the process,the time up to opening and cleaning of the equipment can be prolonged.

[0035] On the other hand, according to still another characteristic ofthe present invention, with respect to a part or component part forwhich the temperature control in a temperature zone sufficiently lowerthan that of a wafer is difficult, when a structure that the bias poweris applied to at least one part thereof is installed in the reactor andthe heat capacity of the whole part is made sufficiently small, thewhole part can be controlled in a high temperature zone without using acomplicated mechanism such as a heater and lamp, so that excessivedeposition of reaction products is controlled and an occurrence offoreign substances caused by peeling of reaction products can bereduced. When the surface area of the part is made smaller, the effecton the process can be controlled even if the temperature and surfacecondition are changed. Furthermore, when the magnitude of bias power tobe applied to the component part is adjusted and the temperature is setwithin a range from 100° C. to 250° C., desirably from 150° C. to 200°C., as compared with a case that the temperature is set within a hightemperature zone of about 250° C. or more, the process is not sensitiveto a change in temperature, so that there is an advantage that thetemperature change of the component part can be made smaller to a levelthat will not substantially affect the process.

[0036] According to still another characteristic of the presentinvention, the temperature of the component part in contact with plasmain the processing chamber can be controlled more actively with highaccuracy in a high temperature zone using infrared radiation and gasheat transfer, so that excessive deposition of reaction products iscontrolled, and an occurrence of foreign substances caused by peeling ofreaction products can be reduced, and the effect on the process also canbe controlled by controlling changes in the temperature and surfacecondition. Furthermore, when the temperature is controlled with theaccuracy of less than ±10° C. within a range from 100° C. to 250° C.,desirably from 150° C. to 200° C., as compared with a case that thetemperature is set within a high temperature zone of about 250° C. ormore, the process is not sensitive to a change in temperature, so thatthere is an advantage that the temperature change of the component partcan be made smaller to a level that will not substantially affect even afiner process.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037]FIG. 1 is a cross sectional schematic diagram of a plasma etchingapparatus which is an embodiment of the present invention.

[0038]FIG. 2 is a drawing showing the temperature control method of asample holder ring which is an embodiment of the present invention.

[0039]FIG. 3 is a drawing showing the temperature control method of aring which is an embodiment of the present invention.

[0040]FIG. 4 is a drawing showing the temperature control method of aring by an infrared lamp which is an embodiment of the presentinvention.

[0041]FIG. 5 is a drawing showing the temperature control method of aring by a refrigerant which is an embodiment of the present invention.

[0042]FIG. 6 is a cross sectional schematic diagram of a magnetic fieldRIE plasma etching apparatus which is an embodiment of the presentinvention.

[0043]FIG. 7 is a cross sectional schematic diagram of a parallel platetype plasma etching apparatus which is an embodiment of the presentinvention.

[0044]FIG. 8 is a cross sectional schematic diagram of an inductivecoupling type plasma etching apparatus which is an embodiment of thepresent invention.

[0045]FIG. 9 is a graph showing the relationship between a number ofprocessed wafers and the temperature of the inner cylinder or jacket ofthe processing chamber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] The embodiments of the present invention will be explainedhereunder with reference to the accompanying drawings.

[0047]FIG. 1 shows an embodiment that the present invention is appliedto a plasma etching apparatus of a magnetic field UHF bandelectromagnetic wave radiation and discharge system and is a crosssectional schematic diagram of the said plasma etching apparatus.

[0048] In FIG. 1, a processing chamber 100 is a vacuum vessel which canrealize the degree of vacuum of about 10⁻⁶ Torr and the apparatus has anantenna 110 for radiating electromagnetic waves as a plasma generationmeans in an upper part of the processing chamber and a lower electrode130 for loading a sample W such as a wafer in a lower part of theprocessing chamber. The antenna 110 and the lower electrode 130 areinstalled opposite to each other in parallel. A magnetic field formingmeans 101 comprising electromagnetic coils 101A and 101B and a yoke 101Cis installed around the processing chamber 100 and a magnetic fieldhaving a predetermined distribution and intensity is formed. By theinteraction of electromagnetic waves radiated from the antenna 110 andthe magnetic field formed by the magnetic field forming means 101,processing gas introduced into the processing chamber is made plasmatic,and plasma P is generated, and the sample W is processed.

[0049] On a side wall or outer cylinder 102 of the processing chamber100, a jacket or inner cylinder 103 for controlling the temperature ofthe inner surface of the side wall is held in the exchangeable state. Aheat exchanging medium is circulated and supplied into the jacket 103from a heat exchanging medium supply means 104 so as to control thetemperature. The temperature of the jacket is controlled with theaccuracy of less than ±10° C. within a range from 0° C. to 100° C.,desirably from 20° C. to 80° C., On the other hand, the processingchamber 100 is evacuated by an evacuation system 106 connected to avacuum chamber 105 and the inside of the processing chamber 100 isadjusted to a predetermined processing pressure within a range from 0.1Pa to 10 Pa, desirably from 0.5 Pa to 4 Pa. The processing chamber 100and the vacuum chamber 105 are set at the grounding potential. Withrespect to the side wall 102 of the processing chamber 100 and thejacket 103, the surface treatment such as plasma resistant anodizedaluminum may be carried out on the surface thereof as a thermallyconductive nonmagnetic metallic material including no heavy metal, forexample, such as aluminum.

[0050] The antenna 110 radiating electromagnetic waves comprises a discelectricity conductor 111, a dielectric 112, and a dielectric ring 113and is held by a housing 114 which is a part of the vacuum vessel. Aplate 115 is installed on the surface of the side of the discelectricity conductor 111 which is in contact with plasma and a ring 116is further installed on the periphery thereof. Processing gas forperforming the processes of etching of samples and film deposition issupplied from a gas supply means 117 at a predetermined flow rate andmixture ratio, controlled to a predetermined distribution via many holesprovided in the disc electricity conductor 111 and the plate 115, andsupplied to the processing chamber 100.

[0051] An antenna power source 121 and an antenna high frequency powersource 122 are connected to the disc electricity conductor 111respectively via filter systems 123 and 124 of the matching circuit andconnected to the ground via a filter 125. The antenna power source 121supplies power at a UHF band frequency desirably within a range from 300MHz to 900 MHz and electromagnetic waves in the UHF band are radiatedfrom the antenna 110. On the other hand, the antenna high frequencypower source 122 applies the bias power, for example, at a low frequencyof about 100 kHz or a high frequency within a range from several MHz toabout 10 MHZ to the disc electricity conductor 111, thus controls thereaction on the surface of the plate 115 in contact with the discelectricity conductor 111. Since the plate 115 is opposite to a wafer,it affects the process most greatly. However, since the bias power isapplied to the surface so as to prevent reaction products fromdeposition, the equipment process is stabilized. Furthermore, forexample, when high-purity silicone or carbon is used as a material ofthe plate 115 in oxide film etching using CF series gas, the F radicalor CFx radical reaction on the surface of the plate 115 is controlledand the radical composition ratio is adjusted. The distance between theunder surface of the plate 115 and the wafer W (hereinafter, it iscalled the gap) is within a range from 30 mm to 150 mm, desirably from50 mm to 120 mm.

[0052] The disc electricity conductor 111 is kept at a predeterminedtemperature by a temperature control means not shown in the drawing,that is, by a heat exchanging medium circulating through it and thesurface temperature of the plate 115 in contact with the discelectricity conductor 111 is controlled. The ring 116 is heated by thebias power from the antenna high frequency power source 122 and thetemperature thereof is controlled. It will be described later in detail.

[0053] At the lower part of the processing chamber 100, the lowerelectrode 130 is installed opposite to the antenna 110. A bias powersource 141 for supplying bias power within a range from 400 kHz to 13.56MHz is connected to the lower electrode 130 via a filter system 142 ofthe matching circuit, controls the bias power to be supplied to thesample W. and is connected to the ground via a filter 143.

[0054] The lower electrode 130 loads and holds the sample W such as awafer on the top thereof, that is, on the sample loading surface by anelectrostatic chucking device 131. On the top of the electrostaticchucking device 131, an electrostatic chucking dielectric layer(hereinafter, abbreviated to an electrostatic chucking film) is formed.The electrostatic chucking device 131 applies a DC voltage within arange from several hundreds V to several kv by an electrostatic chuckingDC power source 144 and a filter 145 so as to generate coulomb forceacting between the sample W and the electrostatic chucking device 131via the electrostatic chucking film and adsorbs and holds the sample Won the lower electrode 130. As an electrostatic chucking film, forexample, an dielectric of aluminum oxide or of a mixture of aluminumoxide and titanium oxide is used.

[0055] Furthermore, the sample W is controlled by a temperature controlmeans not shown in the drawing so that the surface temperature thereofis set to a predetermined temperature so as to control the surfacereaction thereof. For that purpose, to the lower electrode 130, an inertgas, for example, He gas which is set at a predetermined flow rate andpressure is supplied to enhance the thermal conductivity between theelectrostatic chucking device 131 and the sample W. By doing this, thetemperature of a wafer is controlled within a range from 100° C. to 110°C. at its maximum.

[0056] A sample holder ring 132 is installed outside the sample W on thetop of the electrostatic chucking device 131. As a material of thesample holder ring 132, ceramics such as SiC, carbon, silicone, orquartz is used. The sample holder ring 132 is insulated from theelectrostatic chucking device 131 by an insulator 133 such as alumina.Furthermore, by leaking and adding a part of the bias power from thebias power source 141 to the sample holder ring 132 via the insulator133, it is possible to adjust the application of the bias power to thesample holder ring 132 and control the reaction on the surface thereof.For example, when high-purity silicone is used as a material of thesample holder ring 132 in oxide film etching using CF series gas, the Fradical or CFx radical reaction on the surface of the sample holder ring132 is adjusted by the scavenging action of silicone and particularlythe uniformity of etching on the periphery of a wafer can be improved.The sample holder ring 132 is heated by the bias power and cooled byheat transfer gas, thus the temperature thereof is controlled. It willbe described later in detail.

[0057] The plasma etching apparatus in this embodiment is structured asmentioned above and a concrete process, for example, when a siliconoxide film is to be etched using this plasma etching apparatus will beexplained hereunder by referring to FIG. 1.

[0058] Firstly, the wafer W which is an object to be processed istransferred from a sample transfer mechanism not shown in the drawinginto the processing chamber and loaded and chucked on the lowerelectrode 130. The height of the lower electrode is adjusted as requiredso as to be set to a predetermined gap. Next, the inside of theprocessing chamber 100 is evacuated by the evacuation system 106. On theother hand, gases necessary to the etching process of the sample W, forexample, C₄F₈ and Ar are supplied to the processing chamber 100 from theplate 115 of the antenna 110 by the gas supply means 117 at apredetermined flow rate and mixture ratio, for example, at an Ar flowrate of 300 sccm and a C₄F₈ flow rate of 9 sccm. At the same time, theprocessing chamber 100 is evacuated by the evacuation system 106 and theinside of the processing chamber 100 is adjusted to a predeterminedprocessing pressure, for example, 1 Pa. On the other hand, a magneticfield of a predetermined distribution and intensity is formed by themagnetic field forming means 101. Electromagnetic waves in the UHF bandare radiated from the antenna 110 by the antenna power source 121 andplasma P is generated in the processing chamber 100 by the interactionwith the magnetic field. The apparatus dissociates processing gas bythis plasma P so as to generate radical ions and further performs theprocess such as etching to the wafer W by controlling the antenna highfrequency power source 122 and the bias power source 141. When theetching process is finished, the apparatus stops the supply of the powerand processing gas and terminates the etching.

[0059] The plasma etching apparatus in this embodiment is structured asmentioned above and each unit in the reactor, particularly the innersurface of the side wall 103 and the ring 116, and temperature controlof the sample holder ring 132 and deposition control of reactionproducts will be explained in detail hereunder.

[0060] Firstly, the side wall 103 will be explained by referring toFIG. 1. As already explained, the jacket 103 is held inside the sidewall 102 of the processing chamber 100 and the temperature can becontrolled by a heat exchanging medium.

[0061] The inventors have experimented with an object of oxide filmetching at a pressure of 2 Pa using a mixed gas series of C₄F₈ and Ar asa processing gas and as a result of it, we have found that when theinner wall surface temperature in the reactor is controlled to aconstant temperature which is sufficiently lower than the temperature(about 100° C.) of a wafer with the accuracy of less than ±10° C. withina range from 25° C. to 80° C., a strong coating film is formed on theinner wall surface. Within a pressure range of several tens mtorr max.(several Pa max.) like this, ions of high energy increase, so that itcan be considered that the ion assist effect in film deposition isincreased and a tight film is formed. The condition of a deposited filmis such that when the side wall temperature is low, a fine and strongfilm is formed and when the side wall temperature is high, a slightlyrough film is formed. To make this change of film characteristicquantitatively clear, the composition (element density ratio) of a filmdeposited at a side wall temperature of each of 25° C., 50° C., and 80°C. has been analyzed by the XPS (X-ray photoelectron spectroscopy) andthe following results have been obtained. Side wall temperature C(%)F(96) CF ratio 25° C. 45.6 51.1 0.89 50° C. 43.9 53.8 0.82 80° C. 40.658.2 0.70

[0062] The results show that as the side wall temperature lowers, thefilm characteristic becomes richer with carbon. Although not shownabove, the analysis of the C1s peak shows that as the side walltemperature lowers, the bonding of carbon proceeds and thepolymerization also proceeds. It is inferred that this ismacroscopically observed as a fine and strong film.

[0063] During this experiment, the temperature of the side wall surfaceis controlled with the accuracy of less than ±10° C., so that it isforecasted that internal stress caused by a temperature change is notgenerated during deposition of a film and the film structure becomesfine. It is confirmed that a solid layer structure is formed. This filmis very fine and strong and even when a film is deposited tentatively upto a thickness of about 200 microns in the deposition acceleration test,peeling of the film in the tape peeling test or in the friction test arenot observed. Furthermore, this film is highly resistant to plasma andit is acknowledged that peeling and damage of the film surface are notobserved even by the processing of plasma and no dust is caused.

[0064] When the temperature of the inner wall surface of the reactor iscontrolled to a constant temperature which is sufficiently lower thanthe temperature of a wafer as mentioned above, a strong deposited filmfree of occurrence of internal thermal stress can be formed on the innerwall surface of the reactor. This film is highly resistant to plasma andpeeling of reaction products and adhesion of particles onto the samplesurface are reduced, so that it acts as a protection film for the innerwall of the reactor. Therefore, the side wall is free of consumption anddamage, so that the exchange frequency of parts of the side wall can bereduced and the reduction of running cost results. Furthermore, sincethe side wall is protected by the deposited film, there is no need touse ceramics such as SiC which is highly resistant to plasma and thecost of parts can be reduced. If the side wall temperature isparticularly controlled within a range from normal temperature to about50° C., the energy for heating the side wall can be reduced, so that itis effective in energy conservation. As a material of the side wall, athermally conductive metal including no heavy metals, for example,aluminum may be used.

[0065] Since aluminum is exposed in the initial state free of adeposited film, there is the possibility that the surface will bedamaged and deteriorated by plasma. To prevent it, the surface may becoated with a highly polymerized material. Or it is also possible, forexample, to anodize the aluminum surface and then fill fine holes madeby the anodizing process with a highly polymerized material. Needless tosay, the hole filling process can be applied to other than the aluminumanodizing process. When a polymer film exists on the interface betweenthe aluminum surface and the deposited film like this, an effect isproduced that the adherence of the aluminum surface and the depositedfilm is increased and the deposited film is hardly peeled off. A filmmay be excessively deposited depending on the process. If this occurs,it is possible to execute plasma cleaning in a short time after thewafer processing so as to control film deposition and keep the filmthickness constant.

[0066] Next, the sample holder ring will be explained. As alreadyexplained in the embodiment shown in FIG. 1, the sample holder ring 132controls the reaction on the surface thereof by application of the biaspower, thus can make the etching characteristic particularly on theperiphery of a wafer uniform. Although the sample holder ring 132 isheated by the bias power in this case, it is necessary to control theapplied bias power and temperature so as to control the reaction anddeposition of a film on the surface thereof. Moreover, it is desirableto be capable of controlling the applied bias power and temperaturewithout incorporating a complicated mechanism into the lower electrodeincorporated in the electrostatic chucking device 131. This can berealized by control of the leakage bias power and the balance betweenheating by the bias power and cooling by heat transfer gas. Thisembodiment will be explained by referring to the cross sectional view(half on the right) of the lower electrode 130 shown in FIG. 2.

[0067] The lower electrode 130 holds the sample W by the electrostaticchucking device 131. The electrostatic chucking device 131 is insulatedfrom the ground 135 by the insulator 134. In this embodiment, the sampleholder ring 132 is installed opposite to the electrostatic chuckingdevice 131 via the insulator 133, thus structured so that a part of thebias power supplied from the bias power source 141 is leaked and added.The bias power to be applied can be adjusted by the thickness andmaterial of the insulator 133. By use of such a bias power applicationstructure, there is no need to install a wiring structure to the sampleholder ring 132 inside the lower electrode 130 and connect another biaspower source to the sample holder ring 132.

[0068] The electrostatic chucking device 131 is kept at a predeterminedtemperature by circulation of a temperature control heat medium (notshown in the drawing). Between the sample W and the surface of theelectrostatic chucking device 131, a flow path 136 of heat transfer gas(for example, He gas, etc.) is formed and the heat conduction is keptsatisfactory by introduction of heat transfer gas. In this embodiment,flow 136A and 136B of heat transfer gas are also formed between thesample holder ring 132, the insulator 133, and the electrostaticchucking device 131. A part of heat transfer gas for wafer cooling isintroduced and the heat conduction at the contact is kept satisfactory.As a result, the heat conduction between the sample holder ring 132 andthe electrostatic chucking device 131 kept at a predeterminedtemperature is kept satisfactory and the temperature of the sampleholder ring 132 is kept stable. As a result, the temperature change dueto application of the bias power to the sample holder ring 132 iscontrolled and the surface reaction and sample processing characteristicin the sample holder ring 132 can be stabilized. At the same time,deposition of reaction products can be prevented by heating by the biaspower and ion assist, so that peeling of reaction products and adhesionof particles onto the sample surface are reduced.

[0069] As mentioned above, in the sample holder ring, the surfacereaction and temperature and deposition of a film can be controlled by asimple structure by application of the leakage bias power and thebalance between heating by the bias power and cooling by heat transfergas and long term stabilization of the process and reduction of foreignsubstances can be realized.

[0070] In this embodiment, the heat conduction is assured by heattransfer gas. However, another heat conduction means, for example, suchas a thermally conductive sheet may be used.

[0071] Next, the antenna 110 will be explained. As already described inthe embodiment shown in FIG. 1, the antenna high frequency power source122 is connected to the disc electricity conductor 111 and the biaspower at about 100 kHz or within a range from several MHz to about 10MHz is applied. The temperature of the disc electricity conductor 111 iskept at a predetermined value by a heat exchanging medium. Therefore,the plate 115 in contact with the disc electricity conductor 111 isapplied with the bias power and the surface temperature thereof is alsocontrolled. Since the plate 115 is opposite to a wafer, it affects theprocess most greatly. However, when the bias power is applied to thissurface so as to prevent reaction products from deposition and furtherthe surface reaction by the scavenging action is used using high-puritysilicone as a material of the plate, the process can be stabilized.

[0072] On the other hand, the ring 116 on the periphery of the plate 115is heated by the bias power by the antenna high frequency power source122 in the same way as with the plate 115 and moreover the heat capacityof the ring 116 is made smaller, thus the responsibility to temperaturechange is enhanced. This will be explained by referring to FIG. 3.

[0073]FIG. 3 shows an embodiment showing the temperature control methodfor the ring 116. In this embodiment, the ring 116 is structured so thatthe shape thereof is made thinner, and a part thereof covers the plate115, and the thermal contact with the dielectric ring 113 and the plate115 is minimized. When the antenna high frequency power is applied tothe plate 115 in this case, ions are pulled into the surface of the ring116 in the direction of the arrow shown in the drawing by the bias powerto the plate 115. A heating mechanism such a heater and lamp is not usedin this embodiment, so that there is an advantage that the mechanismwill not be complicated.

[0074] The width w of the part of the ring 116 to which the bias poweris applied is set to, for example, 10 mm or more so that the part can beefficiently heated by the bias power. The thickness of the ring 116 isset to, for example, 6 mm or less, desirably 4 mm or less so as to bevalidly heated by the bias power. When the shape is made thinner likethis, the heat capacity of the ring 115 is made smaller. As a result,the whole ring can be heated almost within a range from 100° C. to 250°C., desirably from 150° C. to 200° C., As a result, the deposition ofreaction products is controlled and the occurrence of foreign substancesdue to peeling of reaction products can be reduced. Within thistemperature range, the change in surface reaction is not sensitive tothe change in temperature compared with that in a high temperature zoneof about 250° C. or more, so that there is an advantage that thetemperature change in component parts can be made smaller to such alevel that will not substantially affect the process.

[0075] The thickness of the ring 116 can be decided by the antenna biaspower frequency, the material of the ring 116, and the balance of thedeposition speed of reaction products to the ring 116 so as to controlthe film deposition and prevent the ring surface from sputtering andconsuming by ions. As shown in the drawing, it is possible to make theparts other than the part to be applied with the bias power thinner andmake the heat capacity of the whole ring smaller. When the heat capacityof the ring 116 is made smaller like this, the responsibility issatisfactory in a short time at the initial stage of the process and thetemperature rises, so that the effect on the processing characteristicis small. It is desirable that the inner diameter of the ring 116 islarger than the diameter of a sample. Since the inner diameter of thereactor is about 1.5 times of the diameter of a sample, when thediameter of a sample is 300 mm, the width s of the ring is almost withina range from 50 mm to 70 mm and the surface area thereof is sufficientlysmall for the whole inner wall surface of the reactor, for example, suchas 20% or less. When the surface area of parts is made smaller likethis, even if the temperature and surface condition are changed, theeffect on the process can be controlled. Moreover, since the ring 116 ispositioned on the periphery compared with a wafer, the effect on theprocess is made more smaller.

[0076] In the aforementioned embodiment, since passive heating by plasmais used, a certain degree of temperature change is unavoidable. Thischange may affect the etching characteristic due to fine division of theprocess though the effect is not actualized in the current process andif this occurs, a positive temperature control mechanism by a lamp andheater is required. FIG. 4 shows an embodiment of a temperature controlmechanism by heating of a lamp.

[0077] In this embodiment, the dielectric ring 113A is structured sothat a part thereof can apply the bias power by the same structure 116Aas that of the ring 116 and furthermore, on the side of the dielectricring 113A close to plasma, an infrared absorber 151 for absorbinginfrared light and far infrared light, for example, an aluminum thinfilm is formed. Infrared light and far infrared light are radiated froman infrared radiation means 152, pass through an infrared transmissionwindow 153 and the dielectric ring 113A, are absorbed by the infraredabsorber 151, and heat the ring 116. the infrared absorber 151 can beremotely heated by infrared light, so that when the infrared absorber151 is installed on the side of the dielectric ring 113A close toplasma, the temperature of the surface of the dielectric ring 113Aexposed to plasma can be controlled with higher accuracy. The heatingmechanism uses absorption of infrared light, so that there is anadvantage that the responsibility is better compared with heating by aheating resistor. Furthermore, the dielectric ring 113A is heated alsoby the bias power by the bias power application unit 116A, so that theresponsibility to temperature is improved.

[0078] On the other hand, the infrared radiation means 152 is installedin a holder 154. A gap is provided between the holder 154 and thedielectric ring 113A and heat transfer gas for temperature control issupplied to the gap via a gas supply means 155. Heat transfer gas issealed by vacuum sealing means 156A and 156B. The dielectric ring 113Aradiates heat by this gas heat transfer via the holder 154. Therefore,for example, by heating by the bias power and lamp at start of theprocess and radiating heat by gas heat transfer during the process, theaccuracy of temperature control is improved. As a result, thetemperature of the dielectric ring 113A can be controlled with theaccuracy of about ±5 to 10° C. almost within a range from 100° C. to250° C., desirably from 150° C. to 200° C., The film deposition isreduced at this temperature, so that the occurrence of foreignsubstances due to peeling of a film is controlled. The surface conditionof the dielectric ring 113A is in the region greatly dependent on thetemperature, so that the surface condition is not changed and a plasmaprocess which is stable over a long period is realized.

[0079] In the embodiments shown in FIGS. 3 and 4, the film deposition isreduced by heating the ring 116 in contact with plasma and thedielectric ring 113A. However, the ring in contact with plasma iscontrolled to a constant temperature which is lower than the temperatureof a wafer in the same way as with the inner surface of the side wallexplained in FIG. 1 and a stable deposited film can be formed. FIG. 5shows this embodiment and the dielectric ring 113B is controlled almostwithin a range from 20° C. to 100° C. under temperature control by arefrigerant.

[0080] In this embodiment, a refrigerant for temperature control issupplied to a refrigerant flow path 161 installed in the dielectric ring113B from a heat exchanging medium supply means 162. The refrigerant issealed by a sealing means 163. The temperature of the dielectric ring113B is kept at a predetermined value by a temperature controller andtemperature detector which are not shown in the drawing. By use of thisconstitution, the temperature of the dielectric ring 113B can be keptalmost within a range from 20° C. to 100° C. during plasma processing.Therefore, a stable and strong film of reaction products is deposited onthe surface of the dielectric ring 113B, so that the surface of thedielectric ring 113B will not be etched and consumed. When a film isexcessively deposited depending on the process, the film may be kept ata constant thickness by concurrently using plasma cleaning.

[0081] Each of the aforementioned embodiments uses a plasma etchingapparatus of a magnetic field UHF band electromagnetic wave radiationand discharge system. However, electromagnetic waves to be radiated maybe, for example, microwaves at 2.45 GHz or waves in the VHF band almostwithin a range from several tens MHz to 300 MHz in addition to the UHFband. The magnetic field is not always necessary and, discharge ofnonmagnetic field microwaves, for example, is acceptable.

[0082] Furthermore, in addition to the above, the aforementionedembodiments can be applied to, for example, a magnetron type plasmaetching apparatus using the magnetic field, a plasma etching apparatusof a parallel plate type capacitively coupled system, or an inductivecoupling type plasma etching apparatus.

[0083]FIG. 6 shows an example that the present invention is applied toan RIE apparatus (a magnetron RIE apparatus or magnetically enhanced RIEapparatus). The processing chamber 100 as a vacuum vessel has the sidewall 102, the lower electrode 130 for loading the sample W such as awafer, and an upper electrode 201 to be grounded opposite to it and alsohas the gas supply means 117 for introducing predetermined gas into thevacuum vessel, the evacuation system 106 for decompressing andevacuating the vacuum vessel, an electric field generation means 203 forgenerating an electric field between the lower electrode and the upperelectrode, and a magnetic field generation means 202 for generating amagnetic field inside the vacuum vessel. The magnetic field generationmeans 202 has a plurality of permanent magnets or coils which arearranged in a ring-shape on the periphery of the processing chamber 100and forms a magnetic field almost parallel to the electrodes inside theprocessing chamber. The magnetic field generation means 202 makesprocessing gas plasmatic by the electric field generated between theelectrodes, generates plasma P, and processes the sample W. Furthermore,in the magnetron RIE, a magnetic field is formed almost perpendicularlyto the electric field by the magnetic field generation means 202, sothat the collision frequency between electrons and molecules and atomsin plasma increases, and the plasma density increases, and a highetching characteristic is obtained.

[0084] In this embodiment, in the same way as with the embodimentdescribed in FIG. 1, the jacket 103 for controlling the temperature ofthe inner surface of the side wall is held by the side wall 102 in theexchangeable state, and a heat exchanging medium is circulated andsupplied into the jacket 103 from the heat exchanging medium supplymeans 104, and the temperature of the jacket is controlled with theaccuracy of less than ±10° C. within a range from 0° C. to about 100°C., desirably 20° C. to about 80° C., The jacket 103 comprises, forexample, anodized aluminum.

[0085] By use of this constitution, the inner wall surface of thereactor can be controlled to a constant temperature which issufficiently lower than the temperature of a wafer, so that a strongdeposited film can be formed on the inner surface of the side wall ofthe reactor. This film is highly resistant to plasma and acts as aprotection film for the inner wall of the reactor and peeling ofreaction products and adhesion of particles onto the sample surface arereduced. Therefore, the side wall is free of consumption and damage, sothat the exchange frequency of parts of the side wall can be reduced,and the reduction of running cost results, and there is no need to useceramics such as SiC which is highly resistant to plasma, and the costof parts can be reduced.

[0086] In this embodiment, in the same way as with the embodimentdescribed in FIGS. 1 and 2, it is structured so that a part of the biaspower supplied from the electric field generation means 203 is leaked tothe sample holder ring 132 and furthermore, by cooling by gas heattransfer, the surface reaction and sample processing characteristic inthe sample holder ring 132 can be stabilized. At the same time,deposition of reaction products can be prevented by heating by the biaspower and ion assist, so that peeling of reaction products and adhesionof particles onto the sample surface are reduced.

[0087]FIG. 7 shows an example that the present invention is applied to aparallel plate type plasma etching apparatus. The processing chamber 100as a vacuum vessel has the side wall 102, the lower electrode 130 forloading the sample W such as a wafer, an upper electrode 210 opposite toit, and an electric field generation means 221 for supplying power tothe upper electrode 210 and generating an electric field between theelectrodes. Predetermined processing gas is supplied into the processingchamber 100 by the gas supply means 117 and the vacuum vessel isdecompressed and evacuated by the vacuum system 106. Processing gas ismade plasmatic by the electric field generated between the electrodes,and plasma P is generated, and the sample W is processed. The upperelectrode 210 is held by a housing 214 with an electrode plate 211insulated by insulators 212 and 213. A plate 215 is installed on theside of the electrode plate 211 in contact with plasma and a shield ring216 is installed on the periphery thereof. The shield ring 216 protectsthe insulators 212 and 213 from plasma, simultaneously increases theplasma density by sealing the plasma P in the processing chamber 100 inthe state that it is positioned opposite to the sample holder ring 132,and obtains a high etching characteristic.

[0088] In this embodiment, in the same way as with the embodimentdescribed in FIG. 1, the temperature of the inner surface of the sidewall 102 is controlled by the jacket 103 with the accuracy of less than±10° C. within a range from 0° C. to about 100° C., desirably 20° C. toabout 80° C., so that a deposited film resistant to plasma is formed andacts as a protection film for the inner wall of the reactor, andparticles can be reduced, and the exchange frequency of parts of theside wall can be reduced. Also with respect to the sample holder ring132, the surface reaction and sample processing characteristic can bestabilized by the leakage bias power application structure and gascooling, and the deposition of reaction products is prevented, and theoccurrence of particles is reduced. Furthermore, in the same way as withthe embodiment shown in FIG. 3, the shield ring 216 is structured sothat the shape thereof is thin, and a part of the shield ring 216 coversthe plate 115, and the thermal contact with other parts is minimized. Asa result, when power is applied to the plate 115, the shield ring 216 isheated by ions due to the self bias power, and the deposition ofreaction products is controlled, and the occurrence of foreignsubstances is reduced.

[0089]FIG. 8 shows an example that the present invention is applied toan inductively coupled type plasma etching apparatus. The processingchamber 100 as a vacuum vessel has the side wall 102, the lowerelectrode 130 for loading the sample W such as a wafer, and a top plate230 and is decompressed and evacuated by the vacuum system 106. On thetop of the top plate 230, inductive discharge coils 231 are arranged andhigh frequency power is supplied from a high frequency power source 232.Processing gas is supplied from the gas supply means 117 and madeplasmatic by inductive discharge by the inductive discharge coils 231,and plasma P is generated, and the sample W is processed. In theinductive coupling type plasma etching apparatus, silicone is used as amaterial of the top elate so as to stabilize the process and theinteraction between plasma and the wall is controlled by a means, forexample, a Faraday shield or a magnetic field, thus even if thetemperature of the side wall is made lower than the temperature of awafer, a high etching characteristic can be obtained stably.

[0090] In this embodiment, in the same way as with the embodimentdescribed in FIG. 1, the temperature of the inner surface of the sidewall 102 is controlled by the jacket 103 with the accuracy of less than±10° C. within a range from 0° C. to about 100° C., desirably 20° C. toabout 80° C., As a result, a deposited film resistant to plasma isformed and acts as a protection film for the inner wall of the reactor,and particles can be reduced, and the exchange frequency of parts of theside wall can be reduced. Also with respect to the sample holder ring132, the surface reaction and sample processing characteristic can bestabilized by the leakage bias power application structure and gascooling, and the deposition of reaction products is prevented, and theoccurrence of particles is reduced.

[0091] In the aforementioned embodiments, the processing object issemiconductor wafers and the etching process for them is described.However, the present invention is not limited to it and for example, itcan be applied also to a case that the processing object is a liquidcrystal board and the process itself is not limited to etching but thepresent invention can be applied also to, for example, the sputtering orCVD process.

[0092] In the aforedescribed embodiments, the temperature of the innercylinder or jacket may be detected indirectly, if it cannot be detecteddirectly. However, the following effects can be obtained by attaching atemperature detector to the inner cylinder or jacket.

[0093] (1) By finely adjusting the temperature of the outer cylinder orside wall in order to control the temperature of the inner cylinder orjacket more accurately, controllability of the inner cylinder or jackettemperature can be improved.

[0094] (2) By monitoring the temperature of the inner cylinder orjacket, it is possible to output an alarm signal, such as to indicatethe need for stopping plasma processing or to quit plasma processingwhen the temperature of the inner cylinder or jacket exceeds a presetrange.

[0095] In the embodiments, a heater may be used as the temperaturecontrol function for the outer cylinder or side wall. However, byrecirculating a temperature controlled liquid to the outer cylinder orside wall, it is possible to widen the temperature control range from acooled state below room temperature to a heated state, and accordinglycontrollability of the inner cylinder or jacket temperature can beimproved in this way.

[0096] Further, application of the present invention is not limited tothe case where a process is stabilized by maintaining the temperature ofthe inner cylinder or jacket to a preset value. The present inventioncan be also applied to, for example, a case where an initial processchange for a lot of wafers is corrected by intentionally changing thetemperature of the inner cylinder or jacket at the initial stage of thelot. That is, it is possible to stabilize a process by improving thetemperature controllability for the inner cylinder or jacket duringprocessing of the wafers of the lot as illustrated in FIG. 9.

[0097] The apparatuses described in the aforedescribed embodiments areused as follows.

[0098] Before starting operation of the apparatus, it is checked todetermine whether or not the temperature of the inner cylinder or jacketcan be controlled to a desired temperature.

[0099] Firstly, the inside of the process chamber is evacuated to apreset pressure by action of the vacuum pump. Then, the heater isoperated. The inner cylinder or jacket is heated by heat generation ofthe heater. The temperature of the heated inner cylinder or jacket isdirectly or indirectly detected and controlled to a desired temperature.By doing so, it can be confirmed that the temperature of the innercylinder or jacket can be controlled to the desired temperature. If thetemperature of the inner cylinder or jacket cannot be controlled to thedesired temperature, operation of the heater is stopped. Then, the causeof the trouble is checked and repaired.

[0100] During processing, the temperature of the inner cylinder orjacket is monitored continuously or when required. The monitoredtemperature is compared with a preset desired temperature, and thetemperature of the inner cylinder or jacket is controlled to the desiredtemperature based on the result of the comparison. The temperaturecontrol of the inner cylinder or jacket is performed.

[0101] In general, plural wafers are continuously processed one by one.In such a case, the temperature of the inner cylinder or jacket ismonitored while processing one wafer among them until processing for theall plural wafers is completed to control the temperature to the desiredtemperature. For example, when trouble occurs in the temperaturemonitoring of the inner cylinder or jacket or when the temperature ofthe inner cylinder or jacket cannot be controlled to the desiredtemperature, it is judged that the processing characteristic of thewafer cannot be maintained stable and the wafer processing is stopped.Then, an effort is made to solve the problem, and the successive processfor plural wafers is re-started.

[0102] The fact that trouble occurs in the temperature monitoring of theinner cylinder or jacket or that the temperature of the inner cylinderor jacket cannot be controlled to the desired temperature is indicatedto an operator by output of some kind of alarm through the controller.In response to the alarm, the operator solves the trouble and re-startsthe wafer processing. By monitoring the temperature control of the innercylinder or jacket, the history of the processing up until the stoppingof the wafer processing can be checked, and consequently the search ofthe cause and the repairing method can be performed properly and fast.

[0103] A cleaning process is performed for the inside of the processchamber. The process is performed by wiping the inside surface of theprocess chamber, such as the surface of the inner cylinder or jacket,and the surfaces of parts arranged inside the process chamber, such asthe sample table, or by utilizing a cleaning gas plasma. The process isperformed before a wafer processing, in the intervals betweenprocessings, or after completion of a wafer processing.

[0104] In a case of performing a cleaning process by wiping, it ischecked whether the temperature of the inner cylinder or jacket can becontrolled during a period after completion of the cleaning processingand before the starting of a wafer processing. On the other hand, in acase of performing a cleaning process by utilizing a plasma, it ischecked whether the temperature of the inner cylinder or jacket can becontrolled during the cleaning processing or during a period after thecleaning process and before starting of a wafer processing.

[0105] Further, a discharge running-in (seasoning) process is performedfor the inside of the process chamber. The seasoning process isperformed before starting a wafer processing at the beginning of a day,or during a period after completion of a cleaning processing and beforestarting of a wafer processing. In this case, it may be checked duringthe seasoning process whether the temperature of the inner cylinder orjacket can be controlled or not.

[0106] In order to stabilize the characteristic of plasma processingover time, it is necessary to control the temperature of the innercylinder or jacket to a temperature corresponding to a wafer processingcondition. Here, the wafer processing conditions include the quality offilm to be processed, the kind of processing gas to be used, thecondition of discharge, the type of discharge and so on.

[0107] Therefore, wafer processing conditions are input to thecontroller of the processing apparatus from a higher level controllingunit or an operator. The controller has received an indication of thetemperature of the inner cylinder or jacket corresponding to each of thewafer processing conditions. In the controller, the temperature of theinner cylinder or jacket corresponding to the input wafer processingcondition is selected and set as a control temperature. On the otherhand, a detected and monitored temperature of the inner cylinder orjacket is input to the controller. The detected and monitoredtemperatures are compared with the control temperature, and thetemperature of the inner cylinder or jacket is controlled to the controltemperature based on the result of comparison.

[0108] Further, in a case where the wafer is, for example, of amulti-layer film structure, the temperature of the inner cylinder orjacket may be controlled to a temperature corresponding to that set forthe quality of each film, the kind of process gas, the condition ofdischarge and so on. By doing so, the characteristic of plasmaprocessing can be finely stabilized over time.

[0109] In a case where a wafer processing performance is varied duringone lot processing after a running-in discharge (seasoning) process, thetemperature of the inner cylinder or jacket may be varied along adesired temperature pattern in order to make the processing performanceuniform.

[0110] According to the present invention, a plasma etching apparatusmaintaining the reproducibility and reliability of the process at a lowcost for a long period of time so as to prevent the etchingcharacteristic from a change with time by controlling the innertemperature of the reactor and the wall surface condition can beprovided.

What is claimed is:
 1. A plasma processing apparatus comprising: aplasma generating unit; a process chamber capable of having an insidepressure thereof reduced; a process gas supply unit for supplying gas tosaid process chamber; a specimen table for holding a specimen; and avacuum pumping unit; and a monitor unit; wherein said process chamberincludes an outer cylinder having the capability of withstanding areduced pressure, and an inner cylinder arranged inside said outercylinder; and wherein said monitor unit enables monitoring of atemperature of said inner cylinder at least one of continuously andoptionally at a time of processing of a specimen.
 2. A plasma processingapparatus according to claim 1, wherein said processing apparatusfurther comprises an inner wall temperature setting unit for setting inadvance a temperature of said inner cylinder corresponding to a plasmaprocessing condition for the specimen, and a monitor temperature inputunit.
 3. A plasma processing apparatus comprising: a plasma generatingunit; a process chamber capable of having an inside pressure reduced; aprocess gas supply unit for supplying gas to said process chamber; aspecimen table for holding a specimen; a vacuum pumping unit; and amonitor unit; wherein said process chamber includes an outer cylinderhaving the capability of withstanding a reduced pressure and an innercylinder arranged inside said outer cylinder; and wherein said monitorunit enables monitoring of a temperature of said inner cylindercontinuously for every one of a plurality of specimens until processingof the plurality of specimens is completed when the plurality ofspecimens are processed one by one in a continuous manner.
 4. A plasmaprocessing apparatus according to claim 3, wherein said processingapparatus further comprises an inner wall temperature setting unit forsetting in advance a temperature of said inner cylinder corresponding toa plasma processing condition for the specimen, and a monitortemperature input unit.
 5. A plasma processing apparatus comprising: aplasma generating unit; a process chamber capable of having an insidepressure reduced; a process gas supply unit for supplying gas to theprocess chamber; a specimen table for holding a specimen; a vacuumpumping unit; and a monitor unit; wherein said process chamber includesan outer cylinder having the capability of withstanding a reducedpressure and an inner cylinder arranged inside said outer cylinder;wherein said monitor unit enables monitoring of a temperature of saidinner cylinder at a time of plasma processing for a specimen so that ahistory of the monitoring temperature up to an interruption of theplasma processing for the specimen is inputted and checked.
 6. A plasmaprocessing apparatus according to claim 5, wherein said processingapparatus further comprises an inner wall temperature setting unit forsetting in advance a temperature of said inner cylinder corresponding toa plasma processing condition for the specimen, and a monitortemperature input unit.
 7. A plasma processing apparatus for plasmaprocessing a specimen comprising: a plasma generating unit; a processchamber capable of having an inside thereof pressure reduced; a processgas supply unit for supplying gas to said process chamber; a specimentable for holding the specimen; a vacuum pumping unit; and a monitorunit; wherein said process chamber includes an outer cylinder having thecapability of withstanding a reduced pressure, and an inner cylinderarranged inside said outer cylinder; wherein said monitor unit enablesmonitoring of a temperature of said inner cylinder during a seasoningoperation when the seasoning operation is carried out in said processchamber.
 8. A plasma processing apparatus according to claim 7, whereinsaid processing apparatus further comprises an inner wall temperaturesetting unit for setting in advance a temperature of said inner cylindercorresponding to a plasma processing condition for the specimen, and amonitor temperature input unit.
 9. A plasma processing apparatuscomprising: a plasma generating unit; a process chamber capable ofhaving an inside pressure thereof reduced; a process gas supply unit forsupplying gas to said process chamber; a specimen table for holding aspecimen; a vacuum pumping unit; and a monitor unit; wherein saidprocess chamber includes an outer cylinder having the capability ofwithstanding a reduced pressure, and an inner cylinder arranged insidesaid outer cylinder; and wherein said monitor unit enables monitoring atemperature of said inner cylinder one of before starting plasmaprocessing of a specimen and after finishing a cleaning operation ofsaid plasma chamber.
 10. A plasma processing apparatus according toclaim 9, wherein said processing apparatus further comprises an innerwall temperature setting unit for setting in advance a temperature ofsaid inner cylinder corresponding to a plasma processing condition forthe specimen, and a monitor temperature input unit.
 11. A plasmaprocessing apparatus comprising: a plasma generating unit; a processchamber capable of having an inside pressure thereof reduced; a processgas supply unit for supplying gas to said process chamber; a specimentable for holding a specimen; a vacuum pumping unit; a cleaning unit;and a monitor unit; wherein said process chamber includes an outercylinder having the capability of withstanding a reduced pressure, andan inner cylinder arranged inside said outer cylinder; wherein saidcleaning unit enables a cleaning operation of said process chamber underutilization of plasma for gas for cleaning at least one of before plasmaprocessing of a specimen, during the plasma processing for a pluralityof specimens and after the plasma processing of the specimen; andwherein said a monitor unit enables monitoring of a temperature of saidinner cylinder after a cleaning operation and before starting the plasmaprocessing for the specimen.
 12. A plasma processing apparatus accordingto claim 11, wherein said processing apparatus further comprises aninner wall temperature setting unit for setting in advance a temperatureof said inner cylinder corresponding to a plasma processing conditionfor the specimen, and a monitor temperature input unit.
 13. A plasmaprocessing apparatus comprising: a plasma generating unit; a processchamber capable of having an inside pressure thereof reduced; a processgas supply unit for supplying gas to said process chamber; a specimentable for holding a specimen; a vacuum pumping unit; a monitor unit; anda plasma process interruption unit; wherein said process chamberincludes an outer cylinder having the capability of withstanding areduced pressure, and an inner cylinder arranged inside said outercylinder; and wherein said monitor unit enables monitoring of atemperature of said inner cylinder; and wherein said plasma processinginterruption unit enables interruption of plasma processing for thespecimen in response to the monitoring of the temperature of said innercylinder.
 14. A plasma processing apparatus according to claim 13,wherein said processing apparatus further comprises an inner walltemperature setting unit for setting in advance a temperature of saidinner cylinder corresponding to a plasma processing condition for thespecimen, and a monitor temperature input unit.
 15. A plasma processingapparatus comprising: a plasma generating unit; a process chambercapable of having an inside pressure thereof reduced; a process gassupply unit for supplying gas to said process chamber; a specimen tablefor holding a specimen; a vacuum pumping unit; a cleaning unit; and amonitor unit; wherein said process chamber includes an outer cylinderhaving the capability of withstanding a reduced pressure, and an innercylinder arranged inside said outer cylinder, and wherein said cleaningunit enables a cleaning operation of said process chamber underutilization of a plasma for gas for cleaning during processing of aplurality of specimens when the plural specimens are processed one byone in a continuous manner; and wherein said monitor unit enablesmonitoring of a temperature of said inner cylinder after the cleaningoperation and before starting the plasma processing for the specimen.16. A plasma processing apparatus according to claim 15, wherein saidprocessing apparatus further comprises an inner wall temperature settingunit for setting in advance to input a temperature of the inner cylindercorresponding to a plasma processing condition for a specimen, and amonitor temperature input unit.
 17. A plasma processing apparatuscomprising: a plasma generating unit; a process chamber capable ofhaving an inside pressure thereof reduced; a process gas supply unit forsupplying gas to said process chamber; a specimen table for holding aspecimen; a vacuum pumping unit; and an alarm unit; wherein said processchamber includes an outer cylinder having the capability of withstandinga reduced pressure, and an inner cylinder arranged inside said outercylinder; and wherein said alarm unit enables generation of an alarm inresponse to a detected monitoring temperature for said inner cylinder.18. A plasma processing apparatus according to claim 17, furthercomprising a monitor unit for monitoring temperature of said innercylinder and providing an output of the detected monitoring temperature.19. A plasma processing apparatus according to claim 18, wherein saidprocessing apparatus further comprises an inner wall temperature settingunit for setting in advance a temperature of the inner cylindercorresponding to a plasma processing condition for a specimen, and amonitor temperature input unit.
 20. A plasma processing apparatuscomprising: a plasma generating unit; a process chamber capable ofhaving an inside pressure thereof reduced; a process gas supply unit forsupplying gas to said process chamber; a specimen table for holding aspecimen; a vacuum pumping unit; and a monitor unit; wherein saidmonitor unit enables monitoring of a temperature of an inner wall ofsaid process chamber at least one of continuously and optionally at atime of processing a specimen.
 21. A plasma processing apparatusaccording to claim 20, wherein said processing apparatus furthercomprises an inner wall temperature setting unit for setting in advancea temperature of said inner wall in response to a plasma processingcondition for the specimen, and a monitor temperature inputting unit.22. A plasma processing apparatus comprising: a plasma generating unit;a process chamber capable of having an inside pressure thereof reduced;a process gas supply unit for supplying gas to said process chamber; aspecimen table for holding a specimen; a vacuum pumping unit; and amonitor unit; wherein said monitor unit enables monitoring of atemperature of an inner wall of said process chamber continuously forevery one of a plurality of specimens until the processing of pluralityof specimen is completed when the plurality of specimen are processedone by one in a continuous manner.
 23. A plasma processing apparatusaccording to claim 22, wherein said processing apparatus furthercomprises an inner wall temperature setting unit for setting in advancea temperature of the inner cylinder in response to a plasma processingcondition for the specimen, and a monitor temperature inputting unit.24. A plasma processing apparatus comprising: a plasma generating unit;a process chamber capable of having an inside pressure thereof reduced;a process gas supply unit for supplying gas to said process chamber; aspecimen table for holding a specimen; a vacuum pumping unit; and amonitor unit; wherein said monitor unit enables monitoring of atemperature of an inner wall of said process chamber at a time of plasmaprocessing of the specimen so that a history in which the monitortemperature up to an interruption of the plasma processing for thespecimen is inputted and checked.
 25. A plasma processing apparatusaccording to claim 24, wherein said processing apparatus furthercomprises an inner wall temperature setting unit for setting in advancea temperature of the inner wall in response to a plasma processingcondition for the specimen, and a monitor temperature inputting unit.26. A plasma processing apparatus for performing a plasma processing ofa specimen by a plasma processing apparatus comprising: a plasmagenerating unit; a process chamber capable of having an inside pressurethereof reduced; a process gas supply unit for supplying gas to saidprocess chamber; a specimen table for holding a specimen; a vacuumpumping unit; and a monitor unit; wherein said monitor unit enablesmonitoring of a temperature of an inner wall of said process chamberduring a seasoning operation when the seasoning operation is performedin said process chamber.
 27. A plasma processing apparatus according toclaim 26, wherein said processing apparatus further comprises an innerwall temperature setting unit for setting in advance a temperature ofthe inner wall in response to a plasma processing condition for thespecimen, and a monitor temperature inputting unit.
 28. A plasmaprocessing apparatus comprising: a plasma generating unit; a processchamber capable of having an inside pressure thereof reduced; a processgas supply unit for supplying gas to said process chamber; a specimentable for holding a specimen; a vacuum pumping unit; and a monitor unit;wherein said monitor unit enables monitoring of a temperature of aninner wall of said process chamber one of before starting plasmaprocessing of a specimen and after finishing a cleaning operation.
 29. Aplasma processing apparatus according to claim 28, wherein saidprocessing apparatus further comprises an inner wall temperature settingunit for setting in advance a temperature of the inner wall in responseto a plasma processing condition for the specimen, and a monitortemperature inputting unit.
 30. A plasma processing apparatuscomprising: a plasma generating unit; a process chamber capable ofhaving an inside pressure thereof reduced; a process gas supply unit forsupplying gas to said process chamber; a specimen table for holding aspecimen; a vacuum pumping unit; a cleaning unit; and a monitor unit;wherein said cleaning unit enables a cleaning operation of said processchamber under utilization of a plasma for gas for cleaning at least oneof before plasma processing for a specimen, during the plasma processingfor a plurality of specimens and after the plasma processing for thespecimen; and wherein said monitor unit enables monitoring of atemperature of an inner wall of said process chamber after the cleaningoperation and before starting the plasma processing for the specimen.31. A plasma processing apparatus according to claim 30, wherein saidprocessing apparatus further comprises an inner wall temperature settingunit for setting in advance a temperature of the inner cylinder inresponse to a plasma processing condition for the specimen, and amonitor temperature inputting unit.
 32. A plasma processing apparatuscomprising: a plasma generating unit; a process chamber capable ofhaving an inside pressure thereof reduced; a process gas supply unit forsupplying gas to said process chamber; a specimen table for holding aspecimen; a vacuum pumping unit; a monitor unit; and a plasma processinginterruption unit; wherein said monitor unit enables monitoring of atemperature of an inner wall of said process chamber; and wherein saidplasma processing interruption unit enables interruption of plasmaprocessing for the specimen in response to the monitored inner walltemperature.
 33. A plasma processing apparatus according to claim 32,wherein said processing apparatus further comprises an inner walltemperature setting unit for setting to input a temperature of the innerwall in response to a plasma processing condition for the specimen, anda monitor temperature inputting unit.
 34. A plasma processing apparatuscomprising: a plasma generating unit; a process chamber capable ofhaving an inside pressure thereof reduced; a process gas supply unit forsupplying gas to said process chamber; a specimen table for holding aspecimen; a vacuum pumping unit; a cleaning unit; and a monitor unit;wherein said cleaning unit enables a cleaning operation of said processchamber under utilization of plasma of gas for cleaning duringprocessing of a plurality of specimens when the plurality of specimensare processed one by one in a continuous manner; and wherein saidmonitor unit enables monitoring of a temperature of an inner wall ofsaid process chamber after the cleaning operation and before startingthe plasma processing for the specimen.
 35. A plasma processingapparatus according to claim 34, wherein said processing apparatusfurther comprises an inner wall temperature setting unit for setting inadvance a temperature of the inner wall in response to a plasmaprocessing condition for the specimen, and a monitor temperatureinputting unit.
 36. A plasma processing apparatus comprising: a plasmagenerating unit; a process chamber capable of having an inside pressurethereof reduced; a process gas supply unit for supplying gas to saidprocess chamber; a specimen table for holding a specimen; a vacuumpumping unit; and an alarm unit; wherein said alarm unit enablesgeneration of an alarm in response to a detected monitoring temperatureat an inner wall of said process chamber.
 37. A plasma processingapparatus according to claim 36, further comprising a monitor unit formonitoring temperature of the inner wall and providing an output of thedetected monitoring temperature.
 38. A plasma processing apparatusaccording to claim 37, wherein said processing apparatus furthercomprises an inner wall temperature setting unit for setting in advancea temperature of the inner wall in response to a plasma processingcondition for the specimen, and a monitor temperature inputting unit.